1. Field of the Invention
The present invention relates to a heater head for a multi-cylinder, double-acting hot gas engine, such as a Stirling engine, in which each cylinder is surrounded by an annular regenerator unit, the tops of each cylinder and its surrounding regenerator unit being interconnected by a number of heater tubes.
2. Description of the Prior Art
In the past, the heater tubes of hot gas engines connecting a cylinder and its surrounding regenerator unit have been symmetrically arranged and evenly distributed relative to the axis of the cylinder. Therefore, it has been necessary to provide a separate combustion chamber for each cylinder.
It is generally accepted that for automotive use, as well as for other purposes where a high power output per unit of weight and volume is desirable, the double-acting type of hot gas engine is preferred. For that reason and for economic reasons it is desirable to use a single combustion chamber for a number of cylinders and regenerator units. To obtain a suitable heater head configuration for such a hot gas engine, it has been found necessary to design the regenerator units as elements separate from the cylinders, as shown, for example, in U.S. Pat. No. 2,817,950.
Designing the regenerator units as elements separate from the cylinders, however, increases the cost of the heater head.